1. Field of Invention
The invention relates to storing data items in a memory, to reading data items from a memory, and to a storage medium having stored thereon data items.
2. Description of the Prior Art
It is known to use a storage medium of fixed size to store multiple objects which may be subjected to non-reversible (lossy) compression. Such applications include digital still cameras, where images are stored on a flash card, floppy disc or hard-drive. Further, video cameras are known in which multiple recordings are stored on a hard-drive, optical disc or tape. Also known are storage devices such as embedded memories, where it is desirable to minimize the total storage capacity used while still retaining a best possible image quality. Sometimes, a limited number of settings is available to the user to change the trade-off between quality and capacity. For example, video can be recorded in either ‘standard play’ or ‘long play’ mode, or snapshots can be taken at either ‘standard resolution’ or ‘high resolution’. Once a decision has been made to use a certain quality, the decision cannot be changed afterwards, even in those cases where ample storage capacity is still available.
Cormac Herley discloses in 6th International Conference on Image Processing (ICIP '99), vol. 3, Kobe, Japan, 24–28 Oct. 1999, storage of digital camera images. The camera is designed to store a fixed number of images, and a lossy rate controlled compression is used to ensure that each image fits in the space allocated to it.